вход по аккаунту

159

код для вставки на сайт или в блог

ссылки на документ

231
Racial and Urban/Rural Differences in Cervical
Carcinoma in Georgia Medicaid Recipients
John F. C. Sung, Ph.D., M.P.H.
Daniel S. Blumenthal, M.D., M.P.H.
Ernest Alema-Mensah, D.Min.
Gene A. McGrady, M.D., M.P.H.
BACKGROUND. The authors conducted a study of racial and geographic differences
in the occurrence of cervical carcinoma in a population of uniformly low economic
status: Georgia Medicaid recipients.
METHODS. Medicaid reimbursement claims data for 1992 were used to calculate
counts, rates, and black-to-white risk ratios for newly and previously diagnosed
Department of Community Health and Preventive Medicine, Morehouse School of Medicine,
Atlanta, Georgia, and the Drew-Meharry-Morehouse Consortium Cancer Center.
cases of cervical carcinoma in metropolitan Atlanta and in the remainder of the
state.
RESULTS. Among 615,787 female Georgia Medicaid recipients in 1992, 2050 women
(333 per 100,000) had a diagnosis of carcinoma of the cervix. Of 111,208 women
who had received Medicaid assistance continuously from 1988 to 1992 (5-year
eligibles), a new claim for cervical carcinoma was submitted for 110 (99 per
100,000). In both analyses, rates were higher in metropolitan Atlanta than in the
remainder of the state. Black women had significantly higher claims rates than
white women only in metropolitan Atlanta; risk ratios were 3.7 (95% confidence
interval [CI], 1.3–10.8) for new claims among 5-year eligibles, and 3.5 (95% CI,
3.0-4.1) for prevalence. There was no racial disparity in cervical carcinoma rates
in rural areas.
CONCLUSIONS. The current study data suggest a high risk of cervical carcinoma
among metropolitan Atlanta Medicaid recipients, particularly blacks. Data from
rural Georgia (but not Atlanta) support the hypothesis that racial differences in
cervical carcinoma rates would largely disappear in a population of uniform economic status. Cancer 1997;80:231–6. q 1997 American Cancer Society.
Presented in part at Drew-Meharry-Morehouse
Consortium Cancer Center Annual Symposium,
Nashville, Tennessee, March 23–24, 1995.
Supported in part by Drew-Meharry-Morehouse
Consortium Cancer Center Grant #CA49095-05
National Cancer Institute, National Institutes of
Health and MBRS#SO6GMO8248.
Computer data files were provided by the Georgia State Department of Medical Assistance, and
the Centers for Disease Control and Prevention,
Atlanta, Georgia.
Address for reprints: Daniel S. Blumenthal,
M.D., M.P.H., Department of Community
Health & Preventive Medicine, Morehouse
School of Medicine, 720 Westview Drive, S.W.,
Atlanta, GA 30310-1495.
Received February 10, 1997; accepted March
19, 1997.
KEYWORDS: cervical carcinoma, Medicaid, new claim, prevalence, rural health,
urban health.
C
arcinoma of the uterine cervix is the third most common genital
cancer among white women and the most common among African-American women.1 – 3 It is also the most easily detectable cancer
in the preinvasive stage.4,5 There has been a considerable decrease
in the incidence of and mortality from this disease in the past two
decades.1,3,6 However, the incidence rates for both invasive and in
situ carcinoma of the uterine cervix have been consistently twice as
high in black women as in white women. Investigators have attributed this racial difference in part to socioeconomic status. 7 – 9
If the socioeconomic status hypothesis is correct, one would expect the racial discrepancy in the occurrence of cervical carcinoma
to be reduced in populations in which blacks and whites have similar
socioeconomic backgrounds. To test this hypothesis, the authors examined a multiracial population of relatively uniform economic status, the Georgia Medicaid population.
Medicaid is a program providing health insurance to persons
with financial distress regardless of ethnic background. Household
q 1997 American Cancer Society
/ 7b5a$$1173
06-24-97 13:43:36
cana
W: Cancer
232
CANCER July 15, 1997 / Volume 80 / Number 2
financial status is an index of socioeconomic status,
although they are not identical. The authors conducted an analysis of physicians’ reimbursement
claims for cervical carcinoma among Georgia Medicaid recipients. The hypothesis to be tested was that the
diagnosis of cervical carcinoma in Medicaid patients
would occur at a similar rate among blacks and whites,
because they would both meet similar standardized
financial criteria to qualify for Medicaid assistance.9
Thus, the occurrence of cervical carcinoma (i.e., the
rate of new reimbursement claims for this condition)
should be similar in white and African-American recipients. This study also examined the differences between urban and rural status.
MATERIALS AND METHODS
Data bases used for this report include the recipient
files and the physician claim files from 1988 through
1992 in the Georgia Department of Medical Assistance
(DMA), which administers the Medicaid program. No
data earlier than 1988 are available from the Georgia
DMA. Recipient files provide demographic information on Medicaid recipients; claim files provide diagnostic information for reimbursement. Records in
both types of files contain recipients’ unique identification numbers. These identifiers were used to link
diagnoses to individuals, so that each case was
counted only once. Medicaid recipients whose physicians submitted a claim for a diagnosis of cervical carcinoma, (International Classification of Disease, 9th
revision, Code No. 18010) in 1992 were identified once
as prevalence cases for 1992.
Using Medicaid data to establish incidence rates
presents the difficulty of identifying precisely those
persons who should be included in the calculations.
Changes in personal financial circumstances from
time to time for many individuals result in their gaining or losing Medicaid eligibility. During a period of
ineligibility, some of these persons may be diagnosed
with the condition of interest (in this case, cervical
carcinoma). If they later gain (or regain) Medicaid coverage, this diagnosis may appear in the claims files as
‘‘new’’ even though it had been established previously.
To compensate for this uncertainty, the authors
used ‘‘new claims’’ rather than ‘‘incidence’’ and two
models, which were termed ‘‘Model A’’ and ‘‘Model
B.’’ Both models selected new claims shown in the
1992 files. Model A was limited to a cohort of 111,208
women who received Medicaid assistance continuously from 1988 to 1992. Model B was not so limited,
and included all new 1992 claims regardless of Medicaid eligibility from 1988 to 1991. Therefore, women
newly eligible for Medicaid in 1992, or those who had
been intermittently eligible, were included in the
/ 7b5a$$1173
06-24-97 13:43:36
cana
Model B analysis but not in the Model A analysis.
There were 615,787 women in this group.
Model A was the more limited study group because it included only women who had continuously
received Medicaid for 5 years. Although this criterion
eliminated many women who otherwise would have
been eligible for the study, it was unlikely that any of
the women in the Model A analysis had a diagnosis
of cervical carcinoma that was not reported to the
Medicaid program.
Conversely, Model B captured all cases newly reported to Medicaid in 1992; however, the original diagnoses for some of these cases may have been made prior
to 1992, when the patient was not a Medicaid recipient.
The authors also calculated prevalence rates for
the disease in 1992 by identifying all women with a
diagnosis of cervical carcinoma in 1992 regardless of
whether the case was new in 1992 or previously diagnosed. The entire cohort of female Medicaid recipients
in 1992 (615,787) was used as the population for calculating both prevalence rates and new claims rates in
Model B.
There were 5 main diagnosis fields and 28 subfields for comorbidities in the reimbursement claim
files. The authors used the 5 main diagnosis fields and
the first 5 subfields; these covered 95% of diagnoses
listed in the files. Only whites and African Americans
were included in the current report. Racial differentials
for the metropolitan Atlanta area and the nonmetropolitan Atlanta area (the remainder of the state) in
the prevalence and newly claimed cases of cervical
carcinoma were examined by age (õ20 years, 20 – 29
years, 30 – 39 years, 40 – 59 years, and ¢ 60 years).
Crude and age-adjusted rates using the 1970 U.S. population as the standard were calculated. The authors
also used the Mantel-Haenszel pooled point estimate
and the test-based 95% confidence interval (CI) to
measure the black-to-white risk ratio (RMH) using the
contemporary white population as the standard.11 Urbanization was an important socioeconomic indicator.
Because metropolitan Atlanta is the most urbanized
area in Georgia, the authors measured differences between the metropolitan Atlanta area and non-metropolitan Atlanta areas.
RESULTS
A total of 615,787 female individuals (41.0% white and
59.0% black) were Georgia Medicaid beneficiaries in
1992. New claims for cervical carcinoma were submitted for 2050 of these women (333 per 100,00). There
were 111,208 persons (32.7% white and 67.3% black)
who were continuously Medicaid eligible for 5 years,
from 1988 through 1992 (Model A). Of these, 110 (99
per 100,00) were diagnosed with cervical carcinoma.
W: Cancer
Cervical Carcinoma in Medicaid Recipients/Sung et al.
233
TABLE 1
Crude and Age-Adjusted Ratesa (per 100,000) of New Claim and Prevalence Rates of Cervical Carcinoma and Black-to-White Ratios in Georgia
Medicaid Recipients in Metropolitan Atlanta and Other Areas, 1992
Atlanta
Patient’s status
New claim among 5-year eligibles (Model A)
Crude
Age-adjusteda
RMH (95% CI)
New claim regardless of previous eligibility (Model B)
Crude
Age-adjusteda
RMH (95% CI)c
Prevalence
Crude
Age-adjusteda
RMH (95% CI)c
Other
White rate
(no.)
Black
rate (no.)
B/Wb
ratio
White rate
(no.)
Black
rate (no.)
B/Wb
ratio
64.9 (3)
163
1.0
398 (61)
427
3.7 (1.3–10.8)
6.1
2.6
34.7 (11)
65.6
1.0
58.8 (35)
69.9
1.3 (0.7–2.4)
1.7
1.1
213 (84)
242
1.0
565 (656)
478
2.4 (1.9–3.0)
2.7
2.0
68.5 (146)
79.9
1.0
66.8 (165)
81.8
0.93 (0.7–1.2)
0.98
1.20
337 (133)
372
1.0
1283 (1489)
1077
3.5 (3.0–4.1)
3.8
2.9
96.2 (205)
112
1.0
90.2 (223)
118
0.90 (0.8–1.1)
0.94
1.05
B: black; W: white; RMH: black-to-white risk ratio; CI: confidence interval.
a
Age-adjusted against 1970 U.S. population.
b
Black-to-white rate ratio.
c
Risk ratio of Mantel–Haenszel pooled point estimate and test-based 95% confidence interval.
Blacks had overall age-adjusted rates of cervical
carcinoma claims that were significantly higher than
those for white women for both new claims in Model
A (106.0 per 100,000 vs. 70.4 per 100,000; RMH Å 1.9,
95% CI, 1.1 – 3.3) and prevalence (438.1 per 100,000 vs.
146.6 per 100,000; RMH Å 3.5, 95% CI, 3.0 – 4.1). The
physicians’ claims in the Medicaid files did not differentiate between in situ or invasive carcinoma of the
uterine cervix.
Table 1 shows new claim rates in 1992 among the
cohort that was continuously eligible for Medicaid in
1988 – 1992 (Model A), new claim rates among all Medicaid women in 1992 regardless of previous eligibility
(Model B), and prevalence rates among all Medicaid
eligible women in 1992, all measured by race for metropolitan Atlanta and other nonmetropolitan Atlanta
areas. Rates of cervical carcinoma for newly claimed
cases and prevalent cases differed not only by race but
also between the metropolitan and other areas.
In all models, the rates were higher in the Atlanta
metropolitan area than in the nonmetropolitan Atlanta areas, but they were higher in blacks than in
whites only in metropolitan Atlanta. Among women
who were on Medicaid continuously from 1988 to 1992
(Model A), the age-adjusted new claim rates for cervical carcinoma were 69.9 per 100,000 for blacks and
65.6 per 100,000 for whites (RMH Å 1.3, 95% CI, 0.7 –
2.4) in nonmetropolitan Atlanta areas and 427 per
100,000 for blacks and 163 per 100,000 for whites in
metropolitan Atlanta (RMH Å 3.7, 95% CI, 1.3 – 10.8).
/ 7b5a$$1173
06-24-97 13:43:36
cana
For new claims based only on 1992 Medicaid eligibility
(Model B), the racial risk ratio was reduced to 2.4 (95%
CI, 1.9 – 3.0) for the Atlanta area and was 0.93 (95% CI,
0.7 – 1.2) for the nonmetropolitan Atlanta areas. The
prevalence rate for cervical carcinoma was much
higher in metropolitan Atlanta (age-adjusted rates:
1077 per 100,000 for blacks and 372 per 100,000 for
whites) than in nonmetropolitan Atlanta areas (ageadjusted rates: 118 per 100,000 for blacks and 112 per
100,000 for whites). Overall, the prevalence rate was
931.4 per 100,000 in metropolitan Atlanta and 119.2
per 100,000 in the rest of the state.
Table 2 describes the age specific prevalence of
cervical carcinoma claims by area and race in 1992.
The age specific patterns were different in Atlanta
compared with nonmetropolitan Atlanta areas. In
metropolitan Atlanta, the rates increased sharply, with
a peak rate observed in the 20 – 29 year age group for
both races and a black-to-white rate ratio of 4.7. Outside of metropolitan Atlanta, the prevalence rates were
lower in blacks than in whites for most women until
age ¢ 60 years; overall, there was no significant difference in prevalence between races. For the data displayed in both Tables 1 and 2, the black versus white
differences were statistically significant only in metropolitan Atlanta.
DISCUSSION
The incidence rates for invasive carcinoma of the uterine cervix are approximately twice as high in African
W: Cancer
234
CANCER July 15, 1997 / Volume 80 / Number 2
TABLE 2
Age Specific and Age-Adjusteda Cervical Carcinoma Prevalence Rates
(per 100,000) among Georgia Medicaid Populations in Metropolitan
Atlanta and Nonmetropolitan Atlanta Areas by Race
Age (yrs)
Black rate
(no.)
White rate
(no.)
Metropolitan area
õ20
20–29
30–39
40–59
60/
Crude rate
Age-adjusteda
RMH (95% CI)c
495.9 (284)
3530.1 (858)
1528.3 (272)
854.3 (68)
80.1 (7)
1282.8
1077.0
3.5 (3.0–4.1)
168.8 (26)
755.7 (62)
549.9 (25)
583.9 (16)
46.5 (4)
336.8
372.3
1.0
2.9
4.7
2.8
1.5
1.7
3.1
2.9
Nonmetropolitan area
õ20
20–29
30–39
40–59
60/
Crude rate
Age-adjusteda
RMH (95% CI)c
21.0 (24)
170.4 (77)
144.2 (46)
273.8 (56)
56.4 (20)
90.2
117.8
0.9 (0.8–1.1)
33.9 (29)
182.3 (74)
216.0 (49)
243.0 (37)
32.6 (16)
96.2
112.2
1.0
0.6
0.9
0.7
1.1
1.7
0.9
1.05
B/W ratiob
B: Black; RMH: black-to-white risk ratio; CI: confidence interval.
a
Age-adjusted rate against 1970 U.S. population.
b
Black-to-white rate ratio.
c
Risk ratio of Mantel-Haenszel pooled point estimate and test-based 95% confidence interval.
Americans than in whites both in Georgia and nationwide.1,3,6 Chow et al., using cancer registry data (Surveillance, Epidemiology, and End Results [SEER] Program, Georgia Center for Cancer Statistics, Atlanta),
reported that the age-adjusted incidence rates of both
in situ and invasive carcinoma of the uterine cervix
were 51.6 per 100,000 for whites and 81.5 per 100,000
for blacks, with a black-to-white ratio of 1.6 in the
period 1981 – 1983 in metropolitan Atlanta.6
It would have been of interest to link the current
data with SEER data. However, this was not feasible
for several reasons. First, SEER registry data represent
metropolitan Atlanta plus a limited number of rural
counties, whereas the current data represented the
entire state. Second, patients are entered in the SEER
registry regardless of socioeconomic status (and without information on income), whereas the current
study data were limited to low income (Medicaid-eligible) persons. Finally, files on Medicaid recipients do
not share common identifying codes with persons on
the SEER registry.
The current study utilized the Georgia Medicaid
Claims File, an existing administrative data base that
was not created expressly for the purpose of collecting
morbidity data. Such data bases are often used in mor-
/ 7b5a$$1173
06-24-97 13:43:36
cana
bidity and mortality studies and, although these studies are quite useful, there are a number of pitfalls to
be avoided.12 Some of these pitfalls are addressed in
the pharmacoepidemiology literature, because research in this discipline occasionally utilizes Medicaid
data bases.13
In the current study, the authors recognized in
particular that new claims rates could not be compared with population-based incidence rates, even
among women who were continuously on Medicaid
over a 5-year period. Medicaid eligibility criteria are,
in a sense, arbitrary; they vary from state to state and
not all women meeting the criteria necessarily become
recipients. Hence, the authors used the term ‘‘new
claims’’ rather than ‘‘incidence.’’ However, within the
Georgia Medicaid population, comparative data
(black-white, metropolitan/nonmetropolitan) should
be valid.
It should also be noted that Medicaid in Georgia in
1992 was entirely a fee-for-service program. Capitated
health maintenance organization Medicaid contracts
were first introduced in 1996.
The authors found that African-American Medicaid
recipients had a new claim rate that was 3.7 times
higher than that of white women among those who
were continuously Medicaid-eligible from 1988 through
1992 (Model A). It is unlikely that cases diagnosed in
other places or in years before 1992 were misclassified
and counted in 1992 as newly claimed cases in this
analysis. Compared with cervical carcinoma incidence
rates for the general population of Atlanta in 1981–
1983,6 the excess of newly claimed cases in the Medicaid population in the current study was very striking in
metropolitan Atlanta for both whites (163 vs. 51.6 per
100,000) and blacks (427 vs. 81.5 per 100,000).
Moreover, current data suggest that cervical carcinoma incidence rates have declined since the 1980s.
Hence, the current data would appear to identify urban Medicaid recipients as a very high risk population
for this condition. However, some of the difference
in the two studies may be artifactual, the result of
underreporting to the cancer registry or, in Model B,
underregistration for Medicaid among women with no
known health problems. The latter situation would be
the result of the fact that some Medicaid-eligible
women are not actually enrolled in the program until
a health problem is discovered. Although this would
produce an artifactually high claim rate, it is unlikely
to account for a large portion of the difference between
the data of Chow et al. and that of the current study.
In any event, the racial differences in both studies are
still notable.
Risk factors associated with racial discrepancies
in cancer incidence include socioeconomic factors.7,8
W: Cancer
Cervical Carcinoma in Medicaid Recipients/Sung et al.
Therefore, the authors hypothesized that these discrepancies would be lower among populations sharing
a similar economic background. Findings derived from
the Georgia Medicaid population failed to completely
support this hypothesis. The black-to-white risk ratios
for newly claimed cases of cervical carcinoma in 1992
were elevated for women in metropolitan Atlanta in
both analysis models for new claims. The metropolitan
Atlanta black-to-white prevalence ratio was also elevated. However, there was no significant racial discrepancy in any of the three models in the non-metropolitan Atlanta areas. This suggests that there are risk
factors for blacks in the metropolitan Atlanta area that
are much less important among whites.
Because prevalence rates do not well describe risk,
prevalence studies of cancer are rarely conducted. The
cervical carcinoma prevalence in the Georgia Medicaid population (1283 per 100,000) was high, but may
be primarily accounted for by carcinoma in situ. In
the study by Chow et al., 22% of the tumors in white
patients and 37% of the tumors in black patients were
invasive carcinoma for the general population in metropolitan Atlanta in 1981 – 1983.6 Information regarding the stage of the disease at diagnosis was not available in the Georgia Medicaid data; hence, the authors
were not able to distinguish carcinoma in situ from
invasive carcinoma.
The high prevalence and new claim rates for cervical carcinoma in the Medicaid population may be due
to several factors. First, as previously noted, women
diagnosed with cervical carcinoma may have been
more likely than well women to have been enrolled in
Medicaid and to have maintained their enrollment to
obtain needed medical care. Second, some of the cases
in the Model B analysis were likely diagnosed originally prior to 1992, when the patients were not eligible
for Medicaid. Eligibility then resulted from a decline
in household finances. Diseases such as cervical carcinoma may, of course, cause a worsening of family
finances if the family is not covered by health insurance. In fact, African Americans are more likely than
whites to be financially distressed, to be without insurance, and to become eligible for Medicaid.9,14
Finally, of particular importance are the urbanrural differences. In contrast to the Atlanta (urban)
situation, the incidence of cervical carcinoma was relatively low in the nonmetropolitan Atlanta (mostly rural) portions of Georgia. Moreover, the authors’ original hypothesis was borne out in the rural population,
in that there was no racial disparity. These findings
were consistent in both new claim models as well as
the prevalence model. This may reflect a more conservative rural lifestyle in which cervical carcinoma risk
factors are less prevalent among both black and white
/ 7b5a$$1173
06-24-97 13:43:36
cana
235
women. Such risk factors include early onset of sexual
activity, pregnancy at a young age, multiparity, multiple sexual partners, and a history of sexually transmitted disease including human papilloma virus infection.8,15 – 17
It is generally acknowledged that African Americans have more risk factors than whites, even after
adjusting for social variables.17,18 In Georgia, 27.0% of
the population was African American in 1990,19 but
59% of Medicaid recipients were African Americans.
It is likely that African Americans were a more disadvantaged group than whites, even though both were
financially distressed and receiving Medicaid assistance. Similarly, urban Medicaid recipients may have
been more disadvantaged than those in rural areas.
Nonetheless, the authors did not expect a prevalence
rate 3 times higher in blacks than in whites in Georgia
(438 vs. 146 per 100,000) and 7.8 times higher in metropolitan Atlanta than in the rest of the state (931 vs.
119 per 100,000).
These discrepancies could not be explained by differentials in Papanicolaou smear rates by race or by
rural versus urban residence. Claims rates for Papanicolaou smears were low in all age/race/residence
groups; for example, in 1992 14.0% of metropolitan
Atlanta-area black women received a Papanicolaou
smear, as did 15.6% of metropolitan Atlanta-area white
women, 13.0% of nonmetropolitan black women, and
9.8% of nonmetropolitan white women.
The data from the current study do not take duration of domicile into account, but changes in place
of residence would be unlikely to produce artifactual
rural-urban differences in cervical carcinoma rates.
There has been relatively little rural-urban migration
in recent years. Moreover, most of the movement has
been from rural areas (relatively low cervical carcinoma rates) to urban areas (relatively high rates).
Hence, any artifact introduced by changes in place of
residence would tend to minimize the differences that
were detected in this study.
This study suggests that, in urban areas, factors
other than economic status alone are responsible for
the elevated rate of cervical carcinoma observed in
African Americans compared with whites. Despite the
fact that the authors at least partially controlled for
economic status by studying a Medicaid population,
the racial disparity in cervical carcinoma rates was
not diminished. In fact, this disparity in the urban
Medicaid population was greater than expected, with
surprisingly high rates among African Americans, emphasizing the need for intensified primary and secondary prevention programs in this population.
However, the findings of the current study in ‘‘rural’’ areas were consistent with the hypothesis that
W: Cancer
236
CANCER July 15, 1997 / Volume 80 / Number 2
economic differentials are responsible for racial disparities in cervical carcinoma claims. In contrast to
the urban situation, there was no significant difference
in new claims or prevalence rates in blacks compared
with whites, and rates for both groups were lower in
the rural areas. These findings may be lifestyle-related.
2.
3.
4.
5.
6.
7.
8.
Miller BA, Ries LAG, Hankey BF, Kosary CL, Harras A, Devesa
SS, et al., editors. SEER cancer statistics review: 1973–1990.
Bethesda (MD): National Cancer Institute; 1993 NIH Pub.
No. 93-2789.
American Cancer Society. Cancer facts and figures: 1995.
Atlanta: American Cancer Society, 1995.
Greenberg RS, Sung JFC, Liff JM, Clark WS. Incidence and
survival rates for cancer in Atlanta, 1975–1985. J Med Assoc
GA 1988;77:712–9.
Gellman DD. Cervical cancer screening programs. Can Med
Assoc J 1976;114:1003–33.
Stenkvist B, Bergstrom R, Eklund G, Fox CH. Papanicolaou
smear screening and cervical cancer: what can you expect?
JAMA 1984;252:1423–6.
Chow WH, Greenberg RS, Liff JM. Decline in the incidence of
carcinoma in situ of the cervix. Am J Public Health 1986;76:
1322–4.
Devesa SS. Descriptive epidemiology of cancer of the uterine
cervix. Obstet Gynecol 1984;63:605–12.
Cramer DW. Epidemiologic aspects of gynecologic oncology.
In: Knapp RC, Berkowitz RS, editors. Gynecologic oncology.
2nd edition. New York: McGraw-Hill, 1993:201–22.
/ 7b5a$$1173
10.
11.
12.
REFERENCES
1.
9.
06-24-97 13:43:36
cana
13.
14.
15.
16.
17.
18.
19.
Coughlin TA, Ku L, Holahan J. Medicaid since 1980. Washington DC: The Urban Institute Press, 1994:35–65.
International classification of diseases. Ninth revision, clinical modification. 2nd edition. Washington DC: U.S. Government Printing Office; 1980 DHHS Pub. No. PHS80-1260.
Rothman KJ, Boice JD Jr. Epidemiologic analysis with a programmable calculator. Boston: Epidemiology Resources,
1982:1–12.
Kuller LH. The use of existing databases in morbidity and mortality studies [editorial]. Am J Public Health 1995;85:1198–200
Ray WA, Griffin MR. Use of Medicaid data for pharmacoepidemiology. Am J Epidemiol 1989;129:837–49.
U.S. Bureau of the Census. Statistical abstract of the United
States: 1994. 114th edition. Washington, DC: 1994.
Hoskins WJ, Perez CA, Young RC. Gynecologic tumor. In:
DeVita VT, Hellman S, Rosenberg SA, editors. Cancer: principles and practices of oncology. 4th edition. Philadelphia:
J. B. Lippincott, 1993:1152–225.
Slattery ML, Overall JC Jr., Abbott TM, French TK, Robinson
LM, Gardner J. Sexual activity, contraception, genital infections, and cervical cancer: support for a sexually transmitted
disease hypothesis. Am J Epidemiol 1989;130:248–58.
U.S. Congress, Office of Technology Assessment. Costs and
effectiveness of cervical cancer screening in elderly womenBackground Paper, OTA-BP-H-65. Washington DC: U.S.
Government Printing Office, 1990.
Blane D. Social determinants of health- socioeconomic status, social class, and ethnicity [editorial]. Am J Public Health
1995;85:903–4.
U.S. Bureau of the Census. 1990 Census of population and
housing: summary population and housing characteristics.
Washington, DC: U.S. Government Printing Office, 1991.
W: Cancer